CDS view里case - when - else关键字的用法

Requirement

The following mapping logic needs to be implemented in CDS view layer:

if MARA-MTART = “SERV”, then PRODUCT_TYPE = “02”

if MARA-MTART <> “SERV” and PROD_TYPE_CODE = ‘2’, then PRODUCT_TYPE = “02”

otherwise PRODUCT_TYPE = ''01".

View source code: